1. Field of the Invention
The present invention relates to stretch wrapping and, more particularly, a method and apparatus for reversing the orientation of a film web while stretch wrapping a load.
2. Description of the Related Art
In stretch wrapping, a plastic film web is wrapped around a load in a stretched condition to create a package. The film web may have a tacky surface and a non-tacky surface. The film web is wrapped around the load in a spiral pattern such that portions of the film web overlap one another. The adhesiveness of the tacky surface causes the overlapped portions of the spirally wrapped film web to adhere to each other, thereby creating a stronger package.
It is undesirable to wrap the load with the tacky surface of the film web contacting the load, because the film web may adhere to the load. If the film web adheres to the load, it may damage the load upon removal. However, it is also undesirable to have the tacky surface of the film web facing away from the load and forming the outer surface of the package, because the tacky outer surface can make the package harder to handle. To avoid these problems, the film web is wrapped around the load with the tacky surface of the film web facing away from the load, the orientation of the film web is reversed, and the film web is wrapped around the load with the tacky surface facing toward the load. This method of wrapping places a non-tacky surface in contact with the load while allowing a non-tacky surface to form the outer surface of the package.
U.S. Pat. No. 4,409,776 to Usui, incorporated herein by reference, discloses a method and apparatus for wrapping goods with a stretched film web. In Usui, the load is spirally wrapped with an adhesive surface of the film web facing away from the load. After the entire load is covered, a film web supporting frame is inverted, thereby twisting the film web to reverse the orientation of the film web. The film web is then wrapped with the adhesive surface facing inward toward the load and the non-adhesive surface facing outward.